Permanent mold



Ju'ne 22 1926.

` H. S. LEE

PERMANENT MOLD Filed 00T.. 2. 1924 Pea T56 T//v Z//v//v Zn/v? ,M/f

retenue June 22, 1926.

,UNITED STATES PATENT' -@OFI-"lcs,

maar s. LEE, or PLYMOUTH, moment.

rmanmrr norm.

'Ammann med october s, 1924.' serial No. maze.

This invention relates to permanent molds and has for its object a permanent mold' coated with fire or heatgresisting com# pound which becomes a part of the mold for a long period of time. This enables the casting of ferrous metals in ca-st iron molds without the necessity of'subsequent annealing operations to remove the chill.

In the drawings: j

The figure shows a mold coated with my improved' lining.

The substance that I use as the basis of my fine resisting lining is kieselguhr or in- :Eusorial earth. Kieselguhr is a heat-resisting material of a very high efticienc With kieselguhr I use a suitable aci to cut the kieselguhr and to further comminute the particles of the powdered kieselgnhr. In mixing and preparlng my compound I take 0 say a ten or fifteen percent solution of the acid in water. I find that a greatmany acids `or substances are suitable for this purpose, but preferably hydrofluoric acid or hydrochloric acid (muriatic acid), or ammonia 5 will suitably accomplish my purpose. I then f mix thel powdered kieselguhr into this acid and water solution until the parts have been made into a pasty consistenc (water glass) and water. I can use equal parts or such proportions as /a silicate of soda andv 2/3 water. Infact, there may be considerable variation in these vproportions and measurably ood results obtained.

The silicatel o soda is used in order to form an appropriate binder. Silicate of soda or waterg ass is a substance that has fairly high heat-resisting properties and at the same time makes a very desirable binder.

I then mix together this silicate of soda and water and the kieselguhrpaste already lreferred to, in such proportions as to obtain vabout the same consistency as ordinary aint.

This substance is then spread orspraye onto the mold wall and allowed' to dry from 12 to 14 hours. I find that the substance bakes onto the mold and forms a permanent facin or coatin l and that the same will last an 've goo castings for from three-to four t ousand pourin. However, :it will be found mostdesira le, and in fact quite essential, to use in connection with this coatm a superficial coating of. lamp black, which preferably can be smoked on, as by an l I also prepare a mixture o silicate of sodaV acetylene torch. The lamp black, ofcourse,- w111 be applied lbefore each pouring and serves largely as a parting to prevent the casting from sticking to the fire-resisting coating and stripping part of the coating ofi' when the casting is removed.

My improved heat-resisting coating is very eicient 1n two respects. One of the purposes of the coating is to protect the metaly of the mold from being melted by the exr treme heat of the contents of the mold. "Another very importantfunction that is accomplished by the kieselguhris to prevent heat exchange and protect the casting itself l in chilling. It is a well lknown fact in making steel and iron castings that iron mold parts can be used to chill the casting. A chilled casting can not ordinarily be used as it is impossible to properly machine chilled iron. In those permanent molds, where iron has been used, it has been usually found necessary to anneal the castings after Wards in order to remove the chill. By using my improved coating I find that this chilling of the iron is avoided and annealing is' unnecessary in order to prepare the cast ings for machining.

I find that the acid for comminuting can be omitted, but I prefer to use this as it givesv better results. Y

' What I claim is: i

1..A mold, having a body built of a substance calculated to melt at a point approximating the meltin point of the substance used in casting, an a baked on heat insulating lining for said mold comprising kieselvguhr and a. suitable binder.

2. A mold, having a body constructed of -a\` substance calculated to melt at approxi- HARRY s.

msl

loo 

